Downloaded 27 times
![© 2017 Brian Campbell 11
Do you even bind tokens, bro?
Client Server
ClientHello
...
token_binding [24]
token_binding_version [1,0]
key_parameters_list [2,0]
ServerHello
...
token_binding [24]
token_binding_version [1,0]
key_parameters_list [2]
Key Parameters:
(0) rsa2048_pkcs1.5
(1) rsa2048_pss
(2) ecdsap256
Also need extenstions:
Extended Master Secret
Renegotiation Indication
TLS Handshake](https://image.slidesharecdn.com/cis2017-campbell-tokenbinding-170620232740/85/Beyond-Bearer-Token-Binding-as-the-Foundation-for-a-More-Secure-Web-11-320.jpg)
Uploaded byBrian Campbell
Beyond Bearer: Token Binding as the Foundation for a More Secure Web
The document discusses bearer token binding as a method to enhance web security through a client-generated public-private key pair. It outlines the mechanism of token binding, its application in Single Sign-On (SSO) and OAuth 2.0, and emphasizes its privacy implications. The presentation also highlights ongoing developments in IETF token binding specifications and their adoption in various platforms.
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Beyond Bearer: Token Binding as the Foundation for a More Secure Web
- 1. © 2017 BrianCampbell 1 Beyond Bearer Token Binding as the Foundation for a More Secure Web BRIAN CAMPBELL @__b_c featuring guest contributor MICHAEL B. JONES @selfissued © 2017 Brian Campbell
- 2. © 2017 BrianCampbell 2 Formalities, Introductions, Safe Harbor, etc. • Working for Ping Identity since ’04 – Product Development & Standards – Contributions from Mike Jones, Identity Standards Architect at Microsoft • Pretending to have a different career via CIS since ’11 – Presentation MAY contain gratuitous photos – gratuitous photos • Presentation may contain forward- looking statements and no investment or purchasing decisions should be made based on the content herein – Except to hire a photographer for an obscene amount of money "L'Arroseur Arrosé” by David Brossard
- 3. © 2017 BrianCampbell 3 Formalities, Introductions, Safe Harbor, etc. • Working for Ping Identity since ’04 – Product Development & Standards – Contributions from Mike Jones, Identity Standards Architect at Microsoft • Pretending to have a different career via CIS since ’11 – Presentation MAY contain gratuitous photos • This presentation may contain forward- looking statements and no investment or purchasing decisions should be made based solely on the content herein – Except to hire a photographer for an obscene amount of money "L'Arroseur arrosé” By David Brossard
- 4. © 2017 BrianCampbell 4 The Problem With Bearer Tokens One truth and a lie
- 5. © 2017 BrianCampbell 5 Make HTTP Stateful Again! HttpOnlysecure The archetypal bearer token
- 6. © 2017 BrianCampbell 6 Single Page Apps (everyone is doing it) it's like déjà vu all over again with XSS and local storage
- 7. © 2017 BrianCampbell 7 Token Binding • Enables a long-lived binding via client generated public-private key pair used to sign TLS exported keying material and sent as an HTTP header © 2017 Brian Campbell
- 8. © 2017 BrianCampbell 8
- 9. © 2017 BrianCampbell 9© 2017 Brian Campbell
- 10. © 2017 BrianCampbell 10 Hello! Do you like my extension?
- 11. © 2017 BrianCampbell 11 Do you even bind tokens, bro? Client Server ClientHello ... token_binding [24] token_binding_version [1,0] key_parameters_list [2,0] ServerHello ... token_binding [24] token_binding_version [1,0] key_parameters_list [2] Key Parameters: (0) rsa2048_pkcs1.5 (1) rsa2048_pss (2) ecdsap256 Also need extenstions: Extended Master Secret Renegotiation Indication TLS Handshake
- 12. © 2017 BrianCampbell 12 Token Binding over HTTPS Client Server GET /stuff HTTP/1.1 Host: example.com Sec-Token-Binding: AIkAAgBBQLgtRpWFPN66kxhxGrtaKrzcMtHw7HV8 yMk_-MdRXJXbDMYxZCWnCASRRrmHHHL5wmpP3bhYt0ChRDbsMapfh_QAQ N1He3Ftj4Wa_S_fzZVns4saLfj6aBoMSQW6rLs19IIvHze7LrGjKyCfPT KXjajebxp-TLPFZCc0JTqTY5_0MBAAAA HTTP Request • Encoded Token Binding Message – (1 or more) Token Bindings • Type (provided / referred) • Token Binding ID (key type and public key) • Signature over type, key type, and EKM (TLS Exported Keying Material) • Extensions • Proves possession of the private key on the TLS connection • Keys are long-lived and span TLS connections
- 13. © 2017 BrianCampbell 13 Binding Cookies • The most straightforward application binds a cookie to the Token Binding key • Server associates Token Binding ID with cookie & checks on subsequent use • Augments existing authentication and session mechanisms • Transparent to users • Deployment can be phased in
- 14. © 2017 BrianCampbell 14 Okay, Just Take It Easy Privacy Nerds Advocates • Token Binding is not a supercookie or new big brother tracking mechanism • Client generates a unique key pair per effective top-level domain + 1 (eTLD+1) – E.g., example.com, www.example.com, and etc.example.com share binding but not example.org or example.co.uk • Same scoping rules and privacy implications as cookies © 2017 Brian Campbell
- 15. © 2017 BrianCampbell 15 But what if we need 2Federate? There’s an HTTP response header for that! Tells the browser that it should reveal the Token Binding ID used between itself and the RP (referred) in addition to the one used between itself and the IDP (provided). Browser Identity Provider (IDP)Relying Party (RP) HTTP/1.1 302 Found Location: https://idp.example.com Include-Referred-Token-Binding-ID: true GET / HTTP/1.1 Host: idp.example.com Sec-Token-Binding: ARIAAgBBQB-XOPf5ePlf7ikATiAFEGOS503 lPmRfkyymzdWwHCxl0njjxC3D0E_OVfBNqrIQxzIfkF7tWby2Zfya E6XpwTsAQBYqhFX78vMOgDX_Fd_b2dlHyHlMmkIz8iMVBY_reM98O UaJFz5IB7PG9nZ11j58LoG5QhmQoI9NXYktKZRXxrYAAAECAEFAdU FTnfQADkn1uDbQnvJEk6oQs38L92gv-KO-qlYadLoDIKe2h53hSiK wIP98iRj_unedkNkAMyg9e2mY4Gp7WwBAeDUOwaSXNz1e6gKohwN4 SAZ5eNyx45Mh8VI4woL1BipLoqrJRoK6dxFkWgHRMuBROcLGUj5Pi OoxybQH_Tom3gAA I'll tell you what I'd do, man, two bindings at the same time, man.
- 16. © 2017 BrianCampbell 16 Token Binding for OpenID Connect • Utilizes the Include- Referred-Token- Binding-ID header and the Referred Token Binding • Binds the ID Token to the Token Binding ID the browser uses between itself and the Relying Party • Uses token binding hash “tbh” member of the confirmation claim “cnf”
- 17. © 2017 BrianCampbell 17 “Demo” • Showing a bound: – ID Token SSO – Session Cookie Browser Identity Provider (IDP) https://idp.example.com Relying Party (RP) https://rp.example.io:3000 http://httpbin.org/
- 18. © 2017 BrianCampbell 18 Unauthenticated access request to RP is redirected for SSO
- 19. © 2017 BrianCampbell 19 Authentication request to the IDP
- 20. © 2017 BrianCampbell 20 ID Token delivered to RP
- 21. © 2017 BrianCampbell 21 Authenticated access to RP
- 22. © 2017 BrianCampbell 22 “Demo” Finished
- 23. © 2017 BrianCampbell 23 Token Binding for OAuth Too • Access tokens with referred Token Binding ID • Refresh tokens with provided Token Binding ID • Authorization codes via PKCE – Native app clients – Web server clients
- 24. © 2017 BrianCampbell 24 But What about Client Certificates? • “rarely used in end-user applications” - Wikipedia • Seen specialized/niche deployments rather than large scale • Less than friendly user experience – Comprehending – Obtaining – Using – Logging out – Portability – Managing • Privacy implications RFC 5280 is X.509 Public Key Infrastructure Certificate Profile Denver is nicknamed the Mile-High City because of its 5280 foot elevation Blue Mustang is public art at Denver International Airport Q.E.D.
- 25. © 2017 BrianCampbell 25 The Landscape (some of it anyway) • Three IETF Token Binding specs soon to be RFCs • Draft support – Chrome and Edge/IE (others?!!) – Global on Google servers (since Jan) – .NET Framework (4.6 for server side) – Open source • OpenSSL (https://github.com/google/token_bind) • Apache (https://github.com/zmartzone/mod_token_binding) • NGINX (https://github.com/google/ngx_token_binding) • Java (… er, yeah…) – Online demo at https://www.ietf.org/mail-archive/web/unbearable/current/msg01332.html • OpenID Connect Token Bound Authentication spec is coming along • OAuth 2.0 Token Binding spec is coming along a bit behind that • Working to spec how it’ll work with TLS terminating reverse proxies
- 26. © 2017 BrianCampbell 26 FIN © 2015 Brian Campbell BRIAN CAMPBELL @__b_c featuring guest contributor MICHAEL B. JONES @selfissued
Editor's Notes
- #25 "client certificates are the ‘Hotel California' of identity. 'You can login any time you want but you can never logout’” – from John at IIW